There has been known a recognition apparatus that recognizes patterns of input signals, and converts input signal into a symbol sequence. For example, there have been known a speech recognition apparatus that recognizes speech signals, an optical character recognition (OCR) apparatus that recognizes characters from an image, and the like. In such recognition apparatuses, input signals are divided for each frame, and score calculation and symbol sequence search are performed for each divided frame.
Meanwhile, there exists a recognition apparatus that introduces a symbol representing that information included in an input signal is not a recognition target, and skips search processing when the score of the symbol is large enough. Because such a recognition apparatus skips processing for searching for a symbol that is not a recognition target, calculation costs can be reduced.
Nevertheless, in conventional recognition apparatuses, if symbols that are not recognition targets are skipped too much, a recognition rate declines in some cases.